Technical Field of the Invention
The present invention relates to transparent aqueous gels for topical application, which are suited for artificially tanning and/or browning the skin, and which comprise, formulated into a cosmetically acceptable support therefor, at least one monocarbonyl or polycarbonyl self-tanning agent and at least one water-soluble or water-dispersible, crosslinked or non-crosslinked polymer or copolymer polymerized from at least the acrylamido-2-methylpropanesulfonic acid (AMPS) monomer, in a form partially or totally neutralized with a mineral base other than ammonia.
The present invention also relates to a cosmetic treatment regime or regimen for artificially tanning and/or browning the skin, comprising topically applying thereon, for such period of time as required to elicit the desired effect, a thus effective amount of such a gel composition.
Description of Background and/or Related and/or Prior Art
It is known that monocarbonyl or polycarbonyl compounds, for instance isatin, alloxan, ninhydrin, glyceraldehyde, mesotartaric aldehyde, glutaraldehyde, erythrulose and dihydroxyacetone (DHA) are particularly advantageous products that are commonly included in cosmetics as agents for artificially tanning the skin.
When applied to the skin, especially to the face, these compounds make it possible to obtain a tanning or brown effect that is more or less similar in appearance to that which may result from prolonged exposure to sunlight (natural tanning) or under a UV light. Such a use also has the advantage of totally avoiding the risks of cutaneous reaction generally associated with the abovementioned prolonged exposures (erythemas, burns, loss of elasticity, appearance of wrinkles, premature aging of the skin, and the like).
Transparent cosmetic formulations are more and more appreciated by consumers for aesthetic reasons. Aqueous gels are particularly desired in cosmetics on account of their provision of water, which gives a pleasant sensation of freshness to the skin and due to the fact that they do not have a greasy appearance.
Transparent aqueous gels based on crosslinked acrylic polymers of the Carbomer type, for instance the Carbopol products from Noveon, may be obtained, but these gelling agents are incompatible with self-tanning agents such as dihydroxyacetone (DHA). Thickened aqueous formulations based on hydroxyethylcellulose and hydroxypropyl guar (Jaguar HP from Rhodia) may also be prepared. The products obtained have an unpleasant runny feel, are very tacky after application, and have poor stability over time. The use of cellulose derivatives as gelling agents gives transparent gels that have a tendency to peel on application.
Self-tanning aqueous gels containing a gelling agent of the polyacrylamide type are also described in WO 93/07856, especially Example II comprising dihydroxyacetone, the polyacrylamide/C13-C14 isoparaffin/laureth-7 mixture and benzyl alcohol. This type of composition does not allow transparent gels to be obtained.
An example of a transparent self-tanning gel containing polyacryloyidimethylammonium taurate polymer (crosslinked polymer of acrylamido-2-methylpropanesulfonic acid partially neutralized with ammonia, sold under the trademark Hostacerin AMPS) in combination with a copolymer of anhydride/alkyl vinyl ether (Stabileze QM), is also described in FR-2,816,316. This type of gel is not stable over time.
Need continues to exist for novel self-tanning compositions based on a monocarbonyl or polycarbonyl compound in the form of transparent aqueous gels, which do have the drawbacks indicated above and which have good cosmetic properties: non-runny feel, non-peeling, freshening effect, good stability over time and good self-tanning efficacy on the skin (intensity and staying power for the coloration).